Cummins QSB6.7 Displacement Inboard Marine Diesel Engine

Description

Need heavy shaft torque without excessive fuel burn on extended ocean passages? The Cummins QSB6.7 Displacement Inboard Diesel Engine provides 250 BHP continuous and 305 BHP intermittent output from a 6-Cylinder 6.7L block. Heat exchanger cooling keeps machinery spaces clean, though commercial skippers must maintain rigorous 2-micron fuel pre-filtration to protect sensitive Bosch rail components.

Foundry technicians cast the parent-bore block from gray iron to guarantee structural rigidity across ocean crossings. A single-piece 24-Valve cast iron head optimizes airflow across every combustion cylinder. Marine electrical configurations support 12V or 24V isolated ground circuits to prevent stray current hull damage. The bare engine weighs 1,450 lbs, holding an installation envelope of 49.7in length, 35.4in width, and 33.7in height, with a 4.0 US gal oil pan.

Key Features of Cummins QSB6.7 Displacement Inboard

Long-range yacht captains buy Cummins QSB6.7 Displacement Inboard engines to replace obsolete mechanical propulsion units in heavy steel hulls. This modern package reduces exhaust smell and improves cruise range across remote blue water passages.

• Continuous P1 commercial rating supplies 250 BHP at 2,600 RPM for endless ocean cruising.
• Bosch electronic high-pressure common rail injection optimizes fuel burn across all throttle settings.
• Seawater cooled aftercooler cools incoming boost charge air to increase combustion efficiency.
• SAE 3 flywheel housing bolts to Twin Disc MG-5065A and ZF 280-1A reduction transmissions.
• EPA Marine Tier 3 compliance guarantees low emissions in environmentally sensitive ports.
• Deep commercial oil pan carries 4.0 US gal to prevent lube starvation in rolling seas.
• Freshwater tubular heat exchanger maintains stable engine block thermal balance under continuous load.

Displacement Inboard Dynamometer Test Data

Dynamometer tests verify 250 BHP continuous output at 2,600 RPM with 658 ft-lbs peak shaft torque. Boost pressure stabilizes at 1.85 bar under full load while Bosch injection rail pressure reaches 1,600 bar. The tubular marine heat exchanger holds coolant temperatures at 180°F during extended full load testing. Exhaust pyrometer temperatures read 890°F before the seawater mixing elbow. Lube oil pressure measures 46 PSI at idle and reaches 66 PSI under cruise load with journal runout below 0.0005in TIR.

Displacement Repower Engine Space Guidelines

Electronic CAN bus controls wire to helm stations with 7 lbs of mechanical lever pull force on manual backups. Do not place this commercial workboat diesel engine repower package into lightweight planing skiffs or step-bottom hulls that require high 3,300 RPM rotational speed to achieve planing lift.

• Drain engine oil and install new lube filters every 250 operating hours.
• Replace primary 2-micron fuel water separator filter cartridges every 500 operating hours.
• Inspect heat exchanger raw water zinc anodes every 90 days for galvanic depletion.

Factory Shipping Manifest Warranty Terms

Cummins protects this displacement propulsion engine with a 2-Year or 2,000-Hour commercial marine factory warranty. Each wooden shipping crate contains the complete bobtail engine, 24V starter, 70A marine alternator, flexible isolation engine mounts, engine control harness, oil pressure senders, and official service maintenance manuals.